Add histgrams to Folder shortcut feature in Files.app.

chrome/browser/resources/file_manager/js/navigation_list.js

Index: chrome/browser/resources/file_manager/js/navigation_list.js
diff --git a/chrome/browser/resources/file_manager/js/navigation_list.js b/chrome/browser/resources/file_manager/js/navigation_list.js
index 481e05d9481fa6eb8eb4b3628b68e166fec1f5c4..56ee87472b7ea8dddc39944c758329b1d9a3e79a 100644
--- a/chrome/browser/resources/file_manager/js/navigation_list.js
+++ b/chrome/browser/resources/file_manager/js/navigation_list.js
@@ -313,6 +313,7 @@ NavigationList.prototype.renderRoot_ = function(path) {
 
   var handleClick = function() {
     if (item.selected && path !== this.directoryModel_.getCurrentDirPath()) {
+      metrics.recordUserAction('FolderShortcut.Navigate');
       this.directoryModel_.changeDirectory(path);
     }
   }.bind(this);
@@ -349,6 +350,7 @@ NavigationList.prototype.setContextMenu = function(menu) {
 
 /**
  * Selects the n-th item from the list.
+ *
  * @param {number} index Item index.
  * @return {boolean} True for success, otherwise false.
  */
@@ -361,9 +363,12 @@ NavigationList.prototype.selectByIndex = function(index) {
     return false;
 
   // Prevents double-moving to the current directory.
+  // eg. When user clicks the item, changing directory has already been done in
+  //     click handler.
   if (this.directoryModel_.getCurrentDirEntry().fullPath == newPath)
     return false;
 
+  metrics.recordUserAction('FolderShortcut.Navigate');
   this.directoryModel_.changeDirectory(newPath);
   return true;
 };